Polymerization process utilizing diazabicyclooctane alkylene oxide catalysis



United States Patent POLYMERIZATION PIIOCESS UTILIZING DIAZA- BICYCLOOCTANE ALKYLENE OXIDE CATALY- SIS Burton D. Beitchman, Drexel Hill, Pa., and William E. Erner, Wilmington, Del., assignors to Air Products and Chemicals, Inc., a corporation of Delaware No Drawing. Original application Jan. 17, 1961, Ser. No. 83,150, now Patent No. 3,168,483. Divided and this application June 5, 1964, Ser. No. 377,450

5 Claims. (Cl. 26077.5)

This is a division of US. Patent 3,168,483 which matured from Serial No. 83,150 file-d January 17, 1961.

This invention is directed to new catalysts and new combinations of catalysts useful in the formation of either elastomeric or rigid and either foamed or unfioamed polyurethanes from diisocyanates and polyols. Furthermore, the catalysts and combinations of catalysts herein described are effective in producing controlled polymerization of isocyan'ates to polyisocyanates, e.-g., isocyanate resins.

The catalytic activity of diazabicyclooctane (1,4-diazabicyclo-(2.2.2.)-octane) in eitecting the formation of polyurethane elastomers or foams by the interaction of diisocyanates and 'hydroxy compounds is Well recognized in the polyurethane art, erg, US. #2,939,851. In the extensive development work which has been done since one-shot polyurethane foams were realized for the first time with diazabicyclooctane catalyst, various other components have been added to the polyurethane system or to diazabicyclooctane to assist or modify its catalytic effect. For example, foam stabilizers, such as organosilicones, albumen, or gelatin, have been added to obtain more stable, lower density products; oo-catalysts, such N00 HO alyst J This primary formation of a linear urethane polymer is accompanied:

(a) by a cross-linking reaction, e.g., between ex cess diisocyanate and the secondary NH group of the urethane:

l (catalyst) 3,294,753 Patented Dec. 27, 1966 and/or (b) a blowing or foaming process arising from the reaction of free isocyanate (above that required for urethane formation and cross-linking) and water to form a ureide and release carbon dioxide:

At the same time, isocyanates present in the isocyanatepolyol reaction mixture can be polymerized with tertiary amine catalysts. Such isocyanate polymerization has been described by Arnold, Chem. Rev. 57, 47 (1957) and Kogon, J.A.C.S., 78, 4911 (1956,), who recognized the formation of polymers from pheny-l isocyanates in the presence of tertiary amine catalysts, such as pyridine, triethyl amine, N-methyl morpholine, and the like:

Thus, isocyanates present in the urethane reaction mixture with tertiary amines may be diverted from urethane process requiring active versatile catalysts, or combinations of catalysts selective in producing polymers having the desired density, flexibility, thermal stability, tensile strength and other desired physical and chemical characteristics.

Accordingly, an object of the present invention is the formulation of a catalyst to eitect rapid one-shot addition polymerization of polyols and diisocyanates to produce stable, self-cured elastic or rigid foamed or unfoamed poly-menic resins.

Another object of the present invention is the formulation of catalysts efiective in producing rap-id polymerization of organic isocyanates, which may be copolymerized with polyurethanes as block co-polymers, or may be further polymerized per se to polymeric resins.

Another object of the present invention is the formulation of catalysts based on diazabicyclooctane which are more active, more versatile and less expensive than diazabicyclooctane alone.

These and other objects are accomplished as hereinafter described:

In accordance with the present invention, 1) polymerization of isocyanates and (2) reaction of isocyanates and hydroxy compounds to form urethanes, respectively, are promoted by a catalyst composition consisting of diazabicyclooctane and at least one lower alkylene oxide of the group consisting of ethylene, propylene and butylene oxide.

Since the catalytic effect of diazabicyclooctane in polyurethane systems is well recognized, the novelty of our invention resides in the discovery of the particular phenomena produced by C to C alkylene oxides in conjunction with diazabicyclooctane.

In typical one-shot polyurethane foam preparation a diisocyanate, such as tolylene diisocyanate, is reacted with a polyol, such as polypropylene glycol of about 2000 to 3000 molecular weight in the presence of an effective tertiary amine catalyst such as diazabicyclooctane, water and other additives such as organo-silicone foam stabilizers. The aqueous solution of the catalyst and silicone is usually dissolved in the polyol and this solution then mixed with the diisocyanate. With rapid mixing the batch becomes creamy in a few seconds and, after pouring out, rises to its maximum height in about 1 to 2 minutes. With the proper selection and concentration of catalysts the foamed polyurethane becomes firm and tack-free, though not fully. cured, on standing from 10 to 20 minutes or thereabout at ordinary temperatures. The foamed product is self-curing, i.e., stabilized on longer standing at room temperature. However, to expedite production, the foamed product may be oven cured to a stable, dry product on heating for about 1 hour at ZOO-250 F. In machine made foams the ingredients are mixed instantaneously and the creamed mix is ejected continuously onto a moving belt on which the foam rises to its maximum height in 1 to 3 minutes of belt travel time. These machine made foamed products are generally heat cured to obtain the maximum production rate.

It has now been found that when a small amount of lower aliphatic alkylene oxide is combined with diazabicyclooctane, polyurethane formation is more rapid, and more interestingly, there is a rapid and spontaneous curing with the liberation of heat.

The nature of the accelerating reaction is not yet defined, nor the specific contribution that the alkylene oxides make to the reaction. The several components and their interaction have been studied in various combinations. We have found that (a) hydroxy compounds, such as the polyether polyols used in polyurethane production do not react with diazabicyclooctane with or without alkylene oxides, (b) organic isocyanates do not appear to react at all with alkylene oxides in essentially dry state, isocyanates polymerize only very slowly in the presence of diazabicyclooctane and then principally to form the dimer rather than any higher (solid) polymer, (d) diazabicyclooctane and C to C alkylene oxides react very slowly with each other (over 90 hours) to form a dark oily product. In view of even this very slow reaction of diazabicyclooctane with alkylene oxides, it is preferable to use the diazabicyclooctane-alkylene oxide combination of the instant invention in freshly prepared form or relatively soon after mixing, preferably within 4 to 6 4 hours, and (e) organic isocyanates in the presence of a combination of diazabicyclooctane and a C to C alkylene oxide react rapidly with notable heat generation to form isocyanate polymers or resins.

From these observations it is evident that catalytic polymerization of isocyanates is the key to the reaction. With diazabicyclooctane alone this reaction is relatively slow and exothermic heat is released at a slow, apparently subcritical rate. However, the combination of diazabicyclooctane and C to C alkylene oxides causes the polymerization to go so rapidly that the heat evolved efiects an essentially autocatalytic reaction which may even approach an explosive rate. Thus, diazabicyclooctane and a small amount of an alkylene oxide, such as ethylene, propylene or butylene oxide acting as co-catalysts can apparently produce enough heat by isocyanate polymerization to trigger a broader range polymerization process such as the polyurethane reaction.

The diazabicyclooctane-epoxide catalyzed polymerization of isocyanate can be moderated from a near explosive rate to practical useful levels by the use of smaller quantities of catalysts, solvents or unreactive diluents, or by the gradual addition of a reactant, such as the isocyanate to the reaction mixture.

It is interesting to note that the isocyanate dimerization reaction involves an equilibrium in which dimer is moderately stable at low temperatures, but is highly dissociated or fully dissociated at moderately higher temperatures, for example, with tolylene diisocyanate (Benzene) TDI dimer :2 TDI monomer (Benzene) TDI dimer 2 TDI monomer 0% C.

The role of isocyanate polymerization catalysts and isocyanate polymers in urethane polymerization is clarified considerably by these findings. In a urethane system Where isocyanates are present in a high molar ratio, the formation of isocyanate dimer at low initial temperatures at the initiation of the reaction effectively reduces the .isocyanate concentration and thus buffers the reaction,

especially in slowing down the hydrolysis of isocyanates with the formation of ureides. As the polymerization and condensation reactions progress and warm up, the isocyanate-polymer equilibrium favors polymer dissociation and reactive isocyanate becomes available again for the urethane and ureide reactions. Active isocyanate polymerization catalysts, such as our diazabicyclooctanealkylene oxide combination act to control the polyurethane condensation and foaming processes and effectively distribute the reaction over a broader temperature range to produce more uniform, evenly textured polyurethane foams.

While isocyanates have been polymerized (a) with tertiary amines, (b) with lower C and C alkylene oxides and a tertiary amine such as pyridine and (c) with styrene oxide and diazabicyclooctane, these combinations are invariably slow and inefficient when compared with the combination of C to C alkylene oxides and diazabicyclooctane.

Example I.P0lymerizati0n of aryl isocyanates with alkylene oxides and tertiary amines other than diazabicyclooctane (1) 20 grams of phenyl isocyanate in pyridine solution with two drops of propylene oxide required 24 hours at room temperature to produce a substantial yield of trimer.

(2) 4.8 grams of tolylene diisocyanate (TDI) plus 10 ml. of propylene oxide and 1 drop of pyridine required 24 hours at room temperature to produce a firm gel.

(3) Using similar quantities, TDI in ethylene oxide with 1 drop of pyridine gave the same resulta .gel in 24 hours.

(4) 2.0 grams of phenyl isocyanate in 10 ml. of ethylene oxide and .1 ml. of pyridine yielded the trimer only after 2 days at room temperature or 3 days at C.

(5) TDI with a molecular equivalent of styrene oxide and either triethyl amine or pyridine required 18 hours at room temperature to produce a brittle resin.

(6) Phenyl isocyanate with styrene oxide and t-riethyl amine gave only a viscous polymer on standing overnight (18 hours) at room temperature.

It is apparent that isocyanate polymerization with such catalysts would not contribute sufficient exothermic heat to activate a rapid polyol-isocyanate reaction as is required for one-shot polyurethane formation, nor act as a means of sequestering isocyanates temporarily as lower polymers.

Since isocyanate polymerization is an exothermic reaction, the observed rate of temperature rise or the time elapsed to the maximum temperature observed in the reaction is proportional to the reaction rate. On this basis, propylene oxide and styrene oxide have been compared:

Example lI.Is0cyanate polymerization with diazabicyclooctane comparing propylene oxide and styrene oxide [Using 61 -g.0.35 mol TDI] Time (minutes) Diazabieyclooctane to max.

temperature .25 g, .002 mol Propylene Oxide, 1.7 g., .03 mol. 8 .25 g, .002 mol Styrene Oxide, 3.6 g., .03 11101.--. 48

It is evident that propylene oxide, as a co-catalyst with diazabicyclooctane, is many (approximately 6) times more active than styrene oxide.

The particular efiectiveness of an alkylene oxide (propylene oxide) over epichlorohydrin when used in combination with diazabicyclooctane is shown in a series of experiments with phenyl isocyanate and tolylene diisocyanate:

Example III.-Epichl0r0hydrin vs. propylene oxide A. In phenyl isocyanate polymerization:

Diazabicyclo- Product octane NCO, g. Gel 'lrme,

0.11 g Epichlorohydrin, 11.8 g 10. 5 45 0.10 g Propylene Oxide, 10.0 g 9. 8 3-4 With phenyl isocyanate the combination of diazabicyclooctane and propylene oxide was many fold (11 to 15 time-s) more active than the combination of diazabicyclooctane and epichlorohydrin.

B. Alkylene oxides and diazabicyclooctane in tolylene 1 Slow, sticky White product. 2 Slow, vis. syrup in 180 minutes.

With tolylene diisocyanate, on further evaluation of the alkylene oxides, activity of the alky-lene oxide-diazabicyclooctane combination was highest with ethylene oxide and decreased in the order of ethylene ipropylene butyl ene neohexene octylene, etc. Furthermore, a critical point in the activity values is reached with alkylene oxides higher than butylene oxide. Neohexene oxide gave a slow release of heat (only a 7 C. exotherm was meas ured up to 20 minutes) and the product was a sticky white gel. Octylene oxide was far less active. Even with roughly equi-molar amounts of octylene oxide and isocyanate and the same small amount of diazabicyclooctane, the reaction was very slow, giving a viscous syrup in 1 minutes, with only a small observable temperature rise.

The effective isocyanate polymerization catalyst combination will have from 0.1 mol to 10 mols of diazabicyclooctane to from 0.01 mol to 100 mols of alkylene oxide per 100 mols of isocyanate, or preferably, from 0.5 mol to 5 mols of diazabicyclooctane to from 0.05 mol to 10 mols of alkylene oxide per 100 mols of isocyanate. As has been noted in the examples above, in some cases very small (droplet) amounts of alkylene oxide exert a catalytic effect in the presence of conventional amounts, e.\g., 0.5 to 5 parts of amine catalysts per 100 parts of isocyanat'e. Conversely, with massive quantities of alkylene oxide used as solvent, a distinct catalytic ettect in isocyanate polymerization is shown by very small quantities of amine catalyst. Our invention is demonstrataible with one percent of either of the co-catalysts with the coacting component.

However, a combination of catalysts is proposed in the concentration range preferred above which will give a rapid release of heat .to attain a maximum exotherm in the reaction system in a period of about 8 minutes or less, as shown in Example IIIB.

Example IV A formulation for preparation of an isocyanate resin follows:

Parts wt. Diisocyanato-phenyl methane (1.0 mol) 250 Phenyl isocyanate (0.7 mol) Diazabicyclooctane (.05 mol) 5.5 Propylene oxide (.05 mol) 3.3

An aliquot part of the above ingredients, when mixed and warmed slightly to efiect bulk polymerization, forms a tough yellow gel, in about 2 to 3 minutes. The cold (unreacted) fluid mix can be used to impregnate sample panels of glass ifiber fabric to form laminates having high heat resistance, flexural strength, tensile strength, etc. Six layer laminates prepared by impregnating previously heattreated and dried sheets of glass fabric with the cold bulk reaction mixture, drying and pressing in a mold at 70 to C. at pressures of to 500 p.s.-i., are pale yellow opaque sheets approximately 0.08 inch thick having excellent stability, tensile strength, flexural strength, adhesion and resistance to hydrolysis. Typical tests on such glass laminate panels show:

Wt. percent loss, /2 hr. at 700 F. 9.7 to 11.2 Tensile, lib/in. 33,000 to 45,000 Flexural failure, l b./in. 37,000 to 40,000 Adhesion after hr./ 700 F. Good Tensile after /2 hr./700 F., lb./in. 32,000 to 42,000 Plexural failure after /2 111/700 F.,

1b./in. 22,000 to 28,000 Tensile after 30 days immersion, 1b./

in. 33,000 to 42,000

In view of our discovery of the phenomenal activity of diaz-abicyclooctane when used in combination with a small amount of lower alkylene oxide in catalyzing both urethane formation and organic isocyanate polymerization, it now becomes apparent that isocyanate polymers can be formed rapidly in the presence of this co-catalyst combination and, aside from the eifect of the exothermic heat of polymerization in accelerating the rate of reaction in the Whole system, the isocyanate polymers can react in the urethane system on the basis of free isocyanate groups present, as obtained on dissociation of the dimer, or as remain unreacted in an iso-cyanurate polymer, to form isocyanate modified polyurethanes or urethane modified polyisocyanurates having new and unusual properties. The following scheme shows these reactions:

diisocyanate polyol NCO.

heat I I l dimer isocyanurate trimer with excess NO 0 diazabicyclooctane alkylene oxide catalyst H 0 diazabicyclooctane alkylene oxide catalyst RI alkylene oxide l H 0 catalyst H O isocyanate polymer with excess N C 0 l HO urethane polymer with alkylene oxide catalyst isocyanate polymer with excess alkylene oxide catalyst Polyisocyanates retaining reactive isocyanate groups may also be reacted with (a) alcohols or mixtures of monoand polyols to introduce urethane substituents in the isocyanurate polymer as well as urethane linked polyisocy'anates.

(b) amines to form ureide linked polyisocyanates,

and (c) water (and/or other CO releasing reagents) to form blown ureide linked polyisocyanates, thus producing foamed polyisocyanates,

R-NCO polyisoeyanate water ureide linked polyisoeyanate O 0 II II I 520 N-RNI-I-J3HNRN con urethane polymer isocyanurate urethane polymer isocyanate polymer urethane linked copolymer isocyanate urethane block copolymer An example of such an urethane modified polyisocyanate follows:

Example V To 512 g. of heptadeccanol, 0.25 g. of diazabicyclooctane, 4.0 ml. of propylene oxide and 28.5 ml. of Hylene TM (tolylene diisocyanate, Du Pont, comprising a mixture of of the 2,4-isomer and 20% of the 2,6-isomer) were combined with stirring. Within two minutes the pot temperature rose to about 214 F. and on cooling a pale yellow solid was formed which was deformable like putty but became a rigid solid on further cooling. This product had a molecular weight of 1264 [theory 1290 for 3 (ROHRNCO)]. The higher alcohol reacted produced a hard waxy solid useable as a sealant. Lower alcohols would yield more crystalline polymers. In the absence of propylene oxide, or diazabicyclooctane, or both from the above composition only a urethane type of reaction took place between the alcohol and TDI at room temperature giving a clear water White slightly vviscous liquid. After 15 hours at 150 C. this reaction mixture produced a dark viscous orange syrup, still diflerent from the waxy solid product obtained with diazab icyclooctane and olefin oxide. Heating the orange syrupy reaction mixture still further for 63 hours at 150 C. produced only a dark viscous syrup having a molecular weight of 824 [theory 860 for 2 (ROH-RNCO When Nacconate 300 (National Aniline, 4,4-diphenyl methane diisocyanate) was used instead of Hylene TM in Example 'V with diazabicyclooctane and propylene oxide, a white paste resulted which on heating 1 hour at C. gave a yellow rigid solid.

With a mixture of mono-.and polyols or unsaturated alcohols in the above reaction with diazabicyclooctane and propylene oxide present as co-catalysts, a series of polyvisocyanate-polyol resins was formed having a plastic waxy structure and good coating and sealing characteristcs:

The alkylene (propylene) oxide dissolved in the polyol and the activator solution of catalyst (tin octoate and diazabicyclooctane) and silicone dissolved in water were pumped to the foam machine mixing head. The polyol- Isocyanate-alkanol-poZyol reaction with 0.25 g. diazabicylooctane and 4.0 ml. propylene oxide Quadrol-tetrakis-Q-hydroxypropyl ethylene diamine (Wyandotte Chemical Corporaon). 2 PFC 1000-polypropyleue glycol of 1000 average molecular weight (Carbide Chemical Corporation).

Other modifications in the alcohol-isocyanate reaction activator stream met the TDI stream in the mixing head have been shown to produce novel solid polymers, for example:

9.5 parts of ethanol and 34.8 parts of Hylene TM corresponding to an isocyanate/hydroxyl equivalent ratio of 2/1, were mixed at room temperature and a vigorous reaction ensued resulting in a light yellowlurethane) liquid. The pot temperature rose rapidly to about 140 C. The reaction mixture was then cooled to 28 C. and

0.25 part of diazabicyclooctane and 3.44 parts of propylene oxide added with mixing. A further exothermic reaction took place in which the temperature rose to about 120 C. in fifteen minutes. -On cooling, a white solid resing was obtained which was readily powdered and found soluble in acetone, methyl .isobutyl ketone, toluene and similar solvents.

Urethane modified polyisocyanates of the type here described are an interesting form of blocked isocyanates. In such compounds isocyanate groups are held in combination at ordinary temperatures but release isocyanate groups at higher temperatures to react further in polymer formation. Thus, ethanol, phenol, allyl alcohol and organo-silanols, such as trimethyl silanol, have been reacted with diisocyanates in the presence of diazabicyclooctane and alkylene oxides to form urethane blocked polyisocyanates which were solid to elastomeric polymers at ordinary temperatures but which dissociated in part to reactive isocyanate and hydroxy compound on heating at about 100 to 140 C.

We have also found that elastomers prepared from isocyanates and polyols catalzed by the combination of diazabicyclooctane and alkylene oxides have unusually high resiliency which is not shown by conventional polyurethane elastomers. A number of resilient resins were made, either clear or with various amounts of gas occlusion, as well as both flexible and rigid low density foams.

In the following example, propylene oxide was used at 3 parts per 100 of polyol acting both as -a co-catalyst and as a supplementary blowing agent. The minimum practical effect as a blowing agent was found at 0.5%, while at concentrations as high as 6% or more of propylene oxide the blowing reaction was too rapid, causing a blowing out of the foamed product.

Example VI Duplicate runs were made on the Bayer-Hennecke foam machine using:

and the mixture was ejected through the mixing nozzle onto the machine belt. The creaming time noted was 3 seconds; and the rise time 44 and 46 seconds, respectively. for Foams A and B. The significant physical characteristics of this foamed product are shown under items A and B in the following table. Foams A and B were compared with C, a foam made omitting propylene oxide and with supplemental blowing provided by 10 parts of Freon 11 (trichlorofiuoro-rnethaie) per 100 parts of polyol. The cream time on this run was 6 to 7 seconds and the rise time 75 seconds.

It is evident that 3% of propylene oxide had an accelerating effect on the reaction, giving a notably shorter creaming and rising time than the reference run without propylene oxide. Furthermore, with the exothermic heat of condensation, propylene oxide was volatilized and produced a supplementary blowing effect which gave a lower density product despite supplementary blowing of the reference run' obtained by the addition of '10 wt. percent of Freon 11in the formulation.

A possible difiiculty in making diazabicyclooctane-catalyzed one-shot foams in machine runs is the tendency to overmixing which accelerates the reaction between isocyanates and water causing a premature blowing and a rapid reduction in reactive NCO concentration, thus further slowing down the urethane reaction, by which linear elastomeric polyurethane resins are formed. On the other hand, the rapid polymerization of isocyanates effected by our alkylene oxidediazabicyclooctane catalyst combination apparently acts as a means of holding or sequestering .isocyanates, as e.g., the dimer, thus inhibiting the premature ureide reaction and overcoming the effect of overmixing in the foam machine head. In view of the controlled reaction of isocyanates obtained by our preferred diazabicyclooctane-alkylene oxide combination, the machine foam process can tolerate higher TDI to polyol indices leading, with auxiliary blowing due to propylene oxide, to good load-bearing, ultra-light foams.

1 1 Example VII A butylene oxide-diazabicyclooctane catalyst combination was used in making a casting resin having very good resiliency:

100 par-ts Dow 11-300 polyol, glycerine triol resin 4000 mol. wt.-45 OH number and 33 parts of TDI were mixed and degassed at' 15 mm. Hg

absolute pressure 0.5 part of diazabicyclooctane in 8 parts of butylene oxide were added with stirring.

No creaming was noted in 10 to 15 seconds when the mixture was poured into a mold. It was generally noted that a trace of water as was usually present in organic hydroxy compounds and isocyanates was necessary to give the best reaction and that absolute dryness was not desirable. The mix was degassed by pressure reduction down to 15 mm. Hg. Further, after the mix had been cast, a vacuum was drawn sec. to sec. at 10 mm. Hg) on the mold to eliminate water vapor and avoid bubble formation. A mold of 200 cc. volume gelled in 10 to minutes and was cured (released) in 40 to 60 minutes. The resin ball formed in this example had high resiliency, showing a 60% rebound.

Casting resins as described above can be varied in their properties by using more or less TDI, different alkylene oxides and different hydroxyl equivalent polyols. For example, with 25 parts TDI, less than the 33 parts used in Example VII, a more flexible resin was made showing a 70 to 75% rebound.

A rapid self-curing casting resin was made following Example VII in formulation except having only parts of TDI and 2% of titanium dioxide per 100 parts of polyol as a filler and coloring agent. The mix was poured into a mold patterned on a standard golf ball. The resultant self-cured molded ball, removed after a 60-minute setting time, was a flexible elastic body having a 70-75% rebound and a coherent white surface similar to the commercial vulcanized rubber golf ball.

In theforegoing description and examples where alkylene oxides were employed as co-catalysts with active tertiary amines, such as diazabicyclooctane, the oxide was defined as a C to C alkylene oxide. The basis on Which this limitation was made has been previously considered. In the presence of TDI-polyol mixtures the effect of varying the alkylene oxide used is further shown in the following runs:

Example VIII (a) Non-foamed elastomers were formed:

*LG 56-glycerine polypropoxide trio] of about 3000 mol. wt. having an OH number of 56.

One of the projected uses for the active diazabicyclooctane-alkylene oxide catalyst combination is in the preparation of one-shot rigid foams, using this catalyst combination to effect rapid polymerization and cross-linking and Freon or propylene oxide to effect supplemental blowing. Foams having a heat conductivity [K factor (B.t.u./hr./ft. F./in.)] value of less than 0.14 and as low as 0.11 have been made.

The activity and stability of butylene oxide mark it as the preferred alkylene oxide for non-foamed products. While its rate of self-curing is moderate, it is still very active. Propylene oxide is more active in accelerating the polyurethane reaction and in effecting curing. Since its boils at about 35 C., it exerts its catalytic effect early in the reaction and then with increasing temperature acts as a supplementary blowing agent to produce lighter foams. However, this volatility may be undesirable in certain cases. Eethylene oxide is very active though limited in use since it boils at 10 C. However, for low temperature reactions ethylene oxide and diazabicyclooctane are highly effective. In general, higher C C etc. alkylene oxides are not as active as the C -C group. Condensation and polymerization reactions effected with these oxides are slower and their effect on curing is slight, being essentially the same as for diazabicyclooctane alone. Other lower molecular weight substituted epoxides, such as epichlorohydrin, are relatively inactive and undesirable, as shown in Example III, while higher molecular weight epoxides, such as the epoxide of oleic acid, are definitely less reactive and ineffective. With 5 to 10 parts of epichlorohydrin in the formulation of Example VIII instead of butylene oxide, gel time and mold release time were longer than with butylene oxide, specifically 6 to 8 hours release time compared with 0.7 to 1 hour with butylene oxide.

In the preparation of specific products whether as cast resins or foamed products, such formulations can be Polyol, g. Dow TDI, g. Diazabicy- Alkylene Oxide, g. Description Gel Time 11-300 1 (triol) clooctane, g. in Min.

100 25 0.5 Propylene, 10 Tended to foam rapid 10 self-cure. 100 25 0.5 Butylene, 10 Self-cured 30 100 25 0.5-". Octylene, 10 Slow cure 60 PPG 2000 2 100 37 0.5 None Not gelled after 3 days at room temp. 100 37 0.5 Propylene, 0.34..-. Lightyellow dense solid in 3 days.

(b) Foamed elastomer was formed:

Dow 11-300: 1 100 40 0.5 diazabioyclo- Propylene, 10 Good foam, self-cured octane, 0.8 D.C. with no metal soap 7 199, 2.9 water. present.

1 Dow 11-300-glycerine triol resin, 4000 rnol mol. wt. -45 0H number. 2 PPG 2000-polypropylene glycol, 2.000 mol. wt. 3 D.C. 199o1'gano-silicone, Dow Corning.

Similarly, when TDI and :a triol were reacted in the supplemented by the addition of coloring agents, reinpresence of 0.5% of diazabicyclooctane to form a resin, there was a very pronounced effect of added butylene oxide. In the absence of butylene oxide, it took from 4 to 19 hours (overnight) for the mix to set while 4% of butylene oxide produced a set in 6 to 9 minutes:

forcing agents, fillers, stabilizers and the like. Just as in the above modification of Example VII where 2% of titanium dioxide was incorporated as a filler and coloring agent in a casting resin, carbon black, silica, wood flour, powdered resins can be added' as fillers or extenders, glass fibers and polymeric resin fibers as reinforcing agents, etc. in quantities to obtain the desired physical properties of the composite product.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

What is claimed is:

1. In the process of preparing an organic polymer by the polymerization of a precursor having its principal polymerizable components selected from the group consisting of aryl isocyanates and mixtures of aryl isocyanates with polymers having per molecule a plurality of reactive hydroxyl groups, the improvement which consists of utilizing as the catalyst for the polymerization a composition consisting essentially of the unreacted anhydrous combination of diazabicyclooctane and at least one C -C alkylene oxide in which the mole ratio of diazabicyclooctane to alkylene oxide is from 100 moles of diazabicyclooctane to 1 alkylene oxide to 1 mole of diazabicyclooctane per 20 moles of alkylene oxide.

2. The method of claim 1 wherein said aryl isocyanate is tolylene diisocyanate.

3. The method of claim 1 wherein said alkylene oxide is propylene oxide.

4. In the process of preparing polyurethanes by the polymerization of a precursor having its principal polymerizable components consisting essentially of aryl polyisocyanate and high molecular weight polyhydroxyether polyol, the improvement which consists of utilizing as the catalyst for the polymerization a composition consisting essentially of the unreacted anhydrous combination of diazabicyclooctane and at least one C -C alkylene oxide in which the mole ratio of diazabicyclooctane to alkylene oxide is from 100 moles of diazabicyclooctane to 1 of alkylene oxide to 1 mole of diazabicyclooctane per 20 moles of alkylene oxide.

5. In the process of preparing an organic polymer by the polymerization of a precursor having aryl isocyanates and polyalkylene ether polyols as the principal polymerizable constituents, the improvement Which consists of utilizing as the catalyst for the polymerization a composition consisting essentially of the unreacted anhydrous combination of diazabicyclooctane and at least one C -C alkylene oxide in which the mole ratio of diazabicyclooctane to alkylene oxide is from 100 moles of diazabicyclooctane to l of alkylene oxide to 1 mole of diazabicyclooctane per 20 moles of alkylene oxide.

References Cited by the Examiner UNITED STATES PATENTS 2,939,851 6/1960 Orchin 2602.5 2,979,485 4/1961 Burkus 260- 3,010,963 11/1961 Erner 26077.5 X 3,192,187 6/1965 Beitchman et al. 260-77.5

LEON J. BERCOVITZ, Primary Examiner.

J. J. KLOCKO, Assistant Examiner. 

1. IN THE PROCESS OF PREPARING AN ORGANIC POLYMER BY THE POLYMERIZATION OF A PRECURSOR HAVING ITS PRINCIPAL POLYMERIZABLE COMPONENTS SELECTED FROM THE GROUP CONSISTING OF ARYL ISOCYANATES AND MIXTURES OF ARYL ISOCYANATES WITH POLYMERS HAVING PER MOLECULE A PLURALITY OF REACTIVE HYDROXYL GROUPS, THE IMPROVEMENT WHICH CONSISTS OF UTILIZING AS THE CATALYST FOR THE POLYMERIZATION A COMPOSITION CONSISTING ESSENTIALLY OF THE UNREACTED ANHYDROUS COMBINATION OF DIAZABICYCLOOCTANE AND AT LEAST ONE C2-C4 ALKYLENE OXIDE IN WHICH THE MOLE RATIO OF DIAZABICYCLOOCTANE TO ALKYLENE OXIDE IS FROM 100 MOLES OF DIAZABICYCLOOCTANE TO 1 ALKYLENE OXIDE TO 1 MOLE OF DIAZABICYCLOOCTANE PER 20 MOLES OF ALKYLENE OXIDE. 